After any/all incisions have new skin growing back in, then use Mederma. You can find it at most drug stores, and at Wal-Mart. I used it after my open heart surgery, on my mid-sternum incision. You must wait until incisions have healed to a certain point. It is pricey, but is very soothing, and I believe worked well. I used it for several months. Another good option is liquid vitamin E, or just pierce a vitamin E gelcap and drizzle over the owie. Best of luck to your Sister.
RIP Sasha, best dog ever, pictured shortly before she died. 3/17/12, Jenny has crossed Rainbow Bridge; 5/23/2012 Snowy too now.
Cosmetic grade emu oil is really good for scars and what worked really well for my 2 friends after their mastectomies. But only after they were completely healed to reduce the scars. You can get it online or at just about any health food store. Hugs to your sister.